1. Field of the Invention
The present invention relates to, for example, a semiconductor device, a display device, a light-emitting device, a driving method thereof, and a manufacturing method thereof. In particular, the present invention relates to a light-emitting element, a light-emitting device, an electronic device, and a lighting device each using a dibenzo[c,g]carbazole compound.
2. Description of the Related Art
A light-emitting element (organic EL element) in which an organic compound is used as a light-emitting substance has been progressed because it has advantages that such a light-emitting element can be formed to be thin and lightweight, has very high response speed for input signals, and has low power consumption.
In a light-emitting element, when a voltage is applied between electrodes with a light-emitting layer interposed therebetween, electrons and holes injected from the electrodes recombine to form an excited state, and when the excited state returns to a ground state, light emission is obtained. Since the wavelength of light emitted from a light-emitting substance depends on the light-emitting substance, use of different types of organic compounds for light-emitting substances makes it possible to provide light-emitting elements which exhibit various wavelengths, i.e., various colors.
Light emitted from a light-emitting substance is peculiar to the substance, as described above. However, important performances as a light-emitting element, such as lifetime and power consumption, are not only dependent on the light-emitting substance but also greatly dependent on layers other than a light-emitting layer including the light-emitting substance, an element structure, properties of a light-emitting substance (a guest material) and a host material, compatibility between them, and the like. Thus, many kinds of light-emitting element materials are necessary. For the above-described reasons, light-emitting element materials with a variety of molecular structures have been proposed (e.g., Patent Documents 1 to 4).